The existing micro-channel heat exchanger usually consists of three major parts, i.e., flat tubes, fins and header pipes, wherein the header pipes are usually round and are mainly used for distributing and collecting refrigerant in the flat tubes.
Since the internal spaces of the round header pipes are relatively great, gas refrigerant and liquid refrigerant inside the round header pipes are caused to be separated, consequently the uniform distribution of the refrigerant in the flat tubes is seriously influenced, and usually liquid distribution devices (such as liquid distribution pipes) need to be added to uniformly distribute the refrigerant into each flat tube. Moreover, when the windward size of the micro-channel heat exchanger is limited, the header pipe as a non-heat-exchange unit will occupy certain area, consequently the area of a heat exchange zone is decreased and the heat exchange efficiency of the heat exchanger is reduced; and especially when the flat tubes are relatively wide, the diameter of the header pipe will be increased correspondingly, consequently the cost is increased and the heat exchange area is further decreased.